Turbomachines are machines that operate based on an interaction between a fluid and a machine part. One example of a turbomachine is a gas turbine that uses a fluid (heated gas) to move the blades of a rotor assembly. Another example is a compressor that uses an element such as a piston to compress a fluid (air-gas mixture). Most of these machines are quite complex in structure and contain a large number of components. As is the case with any component, especially a moving component exposed to constant wear and tear, various components of a turbomachine can develop a fault that can lead to a failure of the turbomachine. Consequently, various types of monitoring devices and/or sensor devices are used to constantly monitor the status of various components of the turbomachine and provide early warning of an impending failure or breakdown.
Some faults are relatively easy to monitor and detect, whereas some others are somewhat subtle in nature and difficult to identify. For example, a barely noticeable low-frequency vibration in a component of a turbomachine may lead to a resonant frequency vibration of a much larger magnitude and a sudden catastrophic failure. Some other faults such as a subtle change in the nature of a flow of a hot gas may raise the temperature of a component beyond an operable limit and lead to a breakdown of the component.